Character String Traveling Paths

This section describes steps of connection paths that character strings must travel through in a typical Web based application: output characters strings come from PHP files or data base tables and input character strings come from user's Web browser.

In a typical Web based application, character strings will travel from one part of the application to another part. Here are some possible paths character strings may travel through.

From PHP file to Web browser: The following diagram illustrates steps that character strings must travel through from a PHP file to a browser screen. It also shows the computing technologies that are used at different steps:

A1. Key Sequences from keyboard
      |
      |- Text editor
      v
A2. PHP File
      |
      |- PHP CGI engine
      v
A3. HTML Document
      |
      |- Web server
      v
A4. HTTP Response
      |
      |- Internet TCP/IP Connection
      v
A5. HTTP Response
      |
      |- Web browser
      v
A6. Visual characters on the screen

From Database to Web browser: The following diagram illustrates steps that character strings must travel through from a database table to a browser screen. It also shows computing technologies that are used at different steps:

B1. Byte sequences in storage
      |
      |- Database server
      v
B2. Byte stream
      |
      |- Database connection driver
      v
B3. Byte stream
      |
      |- PHP Application
      v
B4. HTTP Response
      |
      |- Internet TCP/IP Connection
      v
B5. HTTP Response
      |
      |- Web browser
      v
B6. Visual characters on the Screen

From Web browser to Database: The following diagram illustrates steps that character strings must travel from a Web browser to a database table. It also shows computing technologies that are used at different steps:

C1. Key sequences on keyboard
      |
      |- Language input tool (optional)
      v
C2. Byte sequences
      |
      |- Browser input form
      v
C3: HTTP request
      |
      |- Internet TCP/IP Connection
      v 
C4. HTTP request
      |
      |- Web server
      v
C5. CGI variables and input stream 
      |
      |- PHP Application
      v
C6. PHP variables
      |
      |- Database connection driver
      v
C7. Byte stream
      |
      |- Database server
      v
C8. Byte sequence in storage

Since all computing technologies are using ASCII encoding by default, text of ASCII characters can safely travel through those steps without any issues.

However, for non ASCII characters, we have to watch out each steps carefully to make sure that characters are not damaged and are encoded and decoded correctly.

Now I will try to provide some tutorials in this chapter and next 5 chapters to show you how to handle characters correctly in different steps of different connection paths.

Last update: 2015.

Table of Contents

 About This Book

 Introduction and Installation of PHP 7.0

 PHP Script File Syntax

 PHP Data Types and Data Literals

 Variables, References, and Constants

 Expressions, Operations and Type Conversions

 Conditional Statements - "if" and "switch"

 Loop Statements - "while", "for", and "do ... while"

 Function Declaration, Arguments, and Return Values

 Arrays - Ordered Maps

 Configuring and Sending out Emails

 Retrieving Information from HTTP Requests

 Creating and Managing Sessions in PHP Scripts

 Sending and Receiving Cookies in PHP Scripts

 Controlling HTTP Response Header Lines in PHP Scripts

 MySQL Server Connection and Access Functions

 Functions to Manage Directories, Files and Images

 SOAP Extension Function and Calling Web Services

 SOAP Server Functions and Examples

Localization Overview of Web Applications

 What Is Localization / Internationalization?

 Localization of Web Based Applications

Character String Traveling Paths

 Output ASCII Character Strings from PHP Scripts

 Using Non-ASCII Characters in HTML Documents

 Using Non-ASCII Characters as PHP Script String Literals

 Receiving Non-ASCII Characters from Input Forms

 "mbstring" Extension and Non-ASCII Encoding Management

 Managing Non-ASCII Character Strings with MySQL Servers

 Introduction of Class and Object

 Integrating PHP with Apache Web Server

 Outdated Tutorials

 References

 PDF Printing Version